Air conditioning apparatus for cooling or dehumidifying operation



June 28, 1966 w, BB 3,257,822

AIR CONDITIONING APPARATUS FOR COOLING OR DEHUMIDIFYING OPERATION FiledSept. 4, 1964 INVENTOR. ROY W ABBOTT BYW H \s TTORNEY United StatesPatent r 3,257,822 AIR CONDITIONING APPARATUS FOR COOLING 0RDEHUMIDIFYING OPERATION Roy W. Abbott, Jeffersontown, Ky., assignor toGeneral Electric Company, a corporation of New York Filed Sept.4, 1964,Ser. No. 394,411 3 Claims. (Cl. 62-428) tion as an evaporator and theother as a reheat coil during operation of the apparatus as adehumidifier.

Further objects and advantages of the invention will become apparentfrom the following description and the features of novelty whichcharacterize the invention will be pointed out with particularity in theclaims annexed to and forming part of this specification.

In accordance with the present invention there is provided airconditioning apparatus for cooling or dehumidifying air from anenclosure comprising a refrigeration system including a compressor, acondenser, a fixed flow restrictor, first and second heat exchangercoils and unitary valve means for controlling the flow of refrigerantthrough the system so that both of the coils will operate in series asan evaporator or one of the coils will operate as a cooling orevaporating element and the other as a reheat coil. To this end, meansare provided for connecting the compressor, the condenser, a fixed flowrestrictor, the first coil and the second coil in series connection toform a closed circuit for refrigerant fi-ow during cooling operation ofthe apparatus and valve means including a first portion having anormally closed valve opening or port connecting the compressor outletto a portion of the circuit ahead of the first coil section and a secondportion in the circuit between the first and second coils or coilsections. The valve includes a piston separating the first and secondportion and is so constructed that when the valve port is opened topermit flow of high pressure refrigerant from the compressor dischargeto the inlet end of the first coil section, high pressure conditionswithin the valve operate the piston which includes means for restrictingthe flow of refrigerant from the first coil section to the second coilsection thereby causing the first coil section to operate as a condenseror reheat coil and the second c-oil section to continue to operate as anevaporator. Fan means are provided for directing a stream of air throughthe second coil section and then through the first coil section so thatthe air is either cooled by both of the coil sections when the apparatusis operating on the cooling cycle or is cooled for dehumidification andreheated during operation of the apparatus as a dehumidifier.

For a better understanding of the invention reference may be had to theaccompanying drawing in which the single figure illustrates somewhatschematically a refrigeration system of the present invention andelectrical control circuitry for controlling the operation of the systemeither as a cooling unit or as a dehumidifier.

It will be understood that the refrigeration system shown in theaccompanying drawing forms part of air conditioning apparatus which maybe either a room air conditioning unit or a central air conditioningunit.

The refrigeration system includes a compressor 1 connected by adischarge line 2 to an outdoor heat exchanger or condenser 3 in whichhot compressed refrigerant from "ice the compressor is cooled andcondensed by means of a stream of air passed through a duct 4 enclosingthe condenser by means of a fan 5. The condensed or liquid refrigerantflows from the condenser through a strainer or filter 6 and expansionmeans in the form of a capillary flow restrictor 7 to an indoor heatexchanger 8 comprising a first coil or coil section 9 and a second coilor coil section 10 in series connection. Air from within the enclosureis conditioned by being passed through a duct 14 by means of a fan 11 sothat the air passes in series flow first over the second coil section 10and then over the first coil section 9. Refrigerant evaporated in theheat exchanger 8 is withdrawn from the heat exchanger through a suctionline 12 by the compressor 1.

In order that the air conditioning. apparatus may be operated either asa cooling unit or as a dehumidifying unit means are provided foroperation of the coil section 9 either as an evaporator component or asa condenser or reheat coil. This flow control means includes a bypassline 15 connecting the compressor discharge line 2 to the inlet end 16of the coil section 9. A valve generally indicated by the numeral 17includes a first or upper portion 18 containing a valve port 19 andconnected in the bypass line 15 and a second lower portion 20 connectedbetween the two coil sections 9 and 10. A movable piston 21 separatesthe upper and lower portions of the valve and includes a circumferentialslot or groove 22. A spring 23 normally biases the piston 21 to an upperposition to provide unrestricted flow of refrigerant from the first coilsection 9 to the second coil section 10 through the low pressure chamber24 in the lower portion of the valve 17. When the port 19 is opened byenergization of the solenoid 26, the passage'of high pressurerefrigerant from the high pressure inlet chamber 25 above the port 19through the port 19 into the intermediate outlet chamber 27 above thepiston 21 raises the pressure in the chamber and causes the piston 21 tomove downwardly to a position between the inlet 28 to the low pressurechamber 24 and the outlet 29 from this chamber thereby placing the slotor groove 22 between the inlet and outlet and restricting the flow ofrefrigerant from the coil section 9 to the coil section 10.

The specific construction of this valve forms no part I of the presentinvention and for a more detailed desctiption of the structure andoperation thereof, reference is made to Patent 3,132,491 issued May 12,1964 in the name of F. A. Schumacher and assigned to the same assigneeas the present invention.

For cooling operation of the air conditioning apparatus, the port 19 ofthe valve 17 is closed so that the compressor 1, the condenser 3, thecapillary flow restrictor 7, the first coil section 9, the low pressurechamber 23 coil sections 9 and 10 which may be separate heat ex-Uchangers or parts of the same heat exchanger operate as series-connectedevaporator components.

When the valve 17 is operated by the solenoid 26 to open the valve port19, warm and high pressure refrigerant from the compressor 1 is bypassedaround the condenser and the restricting means 7 and is introduceddirectly into the inlet end of the coil section 9. At the same timepiston 21 is forced downwardly between inlet 28 and outlet 29. The flowrestriction provided by the groove or slot 22 in the piston 21isdesigned to provide a fiow restriction such that the refrigerantintroduced into the first coil section 9 will be condensed in that coilsection while the liquid refrigerant introduced into the Patented June28, 1966 second coil section 10 through the slot or groove 22 will beevaporated therein thereby absorbing heat from the air passing over thiscoil section by means of the fan 11. Thus when the apparatus is operatedas a dehumidifier unit air passing through the duct 14 is first cooledso that moisture in the air stream 8 condenses out on the coil 10 afterwhich the cooled air is reheated to substantially its originaltemperature by means of the coil 9 functioning as a condenser or reheatcoil.

The selective operation of the air conditioning apparatus as either acooling unit or as a dehumidifier may be either manually orautomatically controlled. The control circuitry illustratedschematically in the drawing is intended to provide for either manual orautomatic operation whereby the apparatus will operate as a cooling unitwhenever the temperature of the air in the enclosure is above apredetermined temperature and as a dehumidifying unit when thetemperature of that air is below the predetermined temperature.

More specifically, the air conditioner apparatus is provided with athermostat 33 arranged to be responsive to the temperature of the air inthe enclosure as for example the air withdrawn from the enclosurethrough the duct 14 by the fan 11. The thermostat 33 contains a firstbimetal switch 36 connected across lines L1 and L2 for energizing thecompressor Whenever the temperature rises above a predeterminedtemperature such as 70 F. and to de-energize the compressor when thetemperature falls below that temperature. A second bimetal switch 37connected in series with the bimetal switch 36 is adapted to be closedto energize the solenoid 26 whenever dehumidification rather thancooling of the air within the enclosure is desirable, as for example attemperatures below 75 F. A switch 33 is provided for manual controlthereby making it possible to operate the air conditioning apparatus toprovide cooling without reheat that is as a dehumidifier over the entiretemperature range of operation controlled by the switch 36.

By this control arrangement the apparatus operates to cool the enclosureair at all temperatures above a predetermined temperature as for examplea temperature 75 F. while at any temperature between 75 F. and a lowertemperature such as 70 F. closing of the bimetal switch 37 causes theunit to operate as a dehumidifier due to the opening of the valve 17 tobypass refrigerant through the bypass line 15. At temperatures below 70F. opening of the bimetal switch 36 tie-energizes both the compressorand the solenoid operated valve 17 thereby interrupting the operation ofthe apparatus either as a cooling unit or as a dehumidifying unit.

It is to be noted that during operation of the apparatus as adehumidifier, most of the refrigerant flow from the compressor isbypassed through the bypass line 15 to the inlet end of the coil 9.However, a slight flow of refrigerant can take place through thecondenser 3 and the capillary 7 thereby eliminating any possibility oftrapping oil or refrigerant in this portion of the sys-' tem. In otherwords, this portion of the system is opened to the remaining portion ofthe system during operation of the apparatus as a dehumidifier so thatany liquid refrigerant stored therein at the beginning of thedehumidifying cycle will be transferred to the active dehumidificationportion of the circuit.

While there has been shown and described a particular embodiment of thepresent invention it is to be understood that it is not restrictedthereto and it is intended by the appended claims to cover all suchmodifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. An air conditioning apparatus for cooling and dehumidifying air froman enclosure comprising a refrigeration system including a compressor,condenser, a fixed flow restrictor, first evaporator section and secondevaporator section series connected to form a closed normal coolingcircuit,

means for circulating a stream of air from said enclosure in series flowover said second and first evaporator sections,

flow control means for operating said first evaporator section as areheat coil for operation of said apparatus as a dehumidifier,

said flow control means comprising a unitary valve including an inletconnected in said refrigerant circuit between said compressor and saidcondenser and an outlet connected to said circuit between said flowrestrictor and said first evaporator section and a valve port betweensaid inlet and outlet connections and means operable upon opening ofsaid valve port for restricting flow of refrigerant from said firstevaporator section to said second evaporator section whereby said firstevaporator section functions as a reheat coil when said valve port isopen.

2. An air conditioning apparatus for cooling and dehumidifying air froman enclosure comprising a refrigeration system including a compressor,condenser, 21 fixed flow restrictor, first evaporator section and secondevaporator section series connected to form a closed normal coolingcircuit,

means for circulating a stream of air from said enclosure in series flowover said second and first evaporator sections,

flow control means for operating said first evaporator section as areheat coil for operation of said apparatus as a dehumidifier, said flowcontrol means comprising a unitary valve including a first portion and asecond portion,

said first portion having an inlet connected to said refrigerant circuitbetween said compressor and said condenser, and an outlet connected tosaid circuit between said flow restrictor and said first evaporatorsection and a valve port bet-ween said inlet and outlet connections,

said second portion being connected in said circuit between saidevaporator sections,

solenoid means for opening said valve port for the flow of hotcompressed refrigerant gas from said compressor to said first evaporatorsection, said valve including means operable upon opening of said valveport for restricting flow of refrigerant from said first evaporatorsection to said second evaporator section through said second portionwhereby said first evaporator section functions as a reheat coil whensaid valve port is open. 3. An air conditioning apparatus for cooling ordehumidifying air from an enclosure comprising a refrigeration systemincluding a compressor, condenser, a fixed flow restrictor, a first coiland a second coil and unitary valve means for operating said apparatuseither as a cooling unit or as a dehumidifying unit,

said valve including a valve body comprising a high pressure inletchamber at one end of said body, a low pressure chamber at the other endof said body and having spaced inlet and outlet ports, an intermediateoutlet chamber between said high pressure chamber and said low pressurechamber and normally closed valve means between said high pressure andintermediate chambers, a movable piston within said valve body betweensaid intermediate chamber and said low pressure chamber,

means for normally positioning said piston within said valve bodybetween said valve means and said low pressure chamber inlet and outletand for permitting movement of said piston downwardly to a secondposition overlying said inlet and outlet,

means for connecting said compressor, condenser, flow restricting means,first coil section, low pressure chamber, second coil section in seriesconnection to form a closed refrigerant circuit for operation of saidpiston is in said second position whereby said said apparatus as acooling unit, first coil section operates as a condenser and said meansconnecting said compressor, said high pressure second coil sectionoperates as an evaporator when chamber, said intermediate outletchamber, said first 7 said valve means is open.

coil section, said low pressure chamber, said second 5 coil section inclosed series flow refrigerant circuit, References Cited y the Examine!and means for opening said valve means whereby hot UNITED STATES PATENTScompressed refrigerant from the compressor flows v through said highpressure chamber and said outlet gig? chamber to said first coil sectionand said piston 10 3105366 10/1963 62 moves downwardly to its secondposition overlying I said inlet and outlet to said low pressure chamber,3139735 7/1964 Malkofi 62173 said piston including means defining arestricted com- MEYER PERLIN, primary Examiner munication between saidinlet and said outlet when

1. AN AIR CONDITIONING APPARATUS FOR COOLING AND DEHUMIDIFYING AIR FROMAN ENCLOSURE COMPRISING A REFRIGERATION SYSTEM INCLUDING A COMPRESSOR,CONDENSER, A FIXED FLOW RESTRICTOR, FIRST EVAPORATOR SECTION AND SECONDEVAPORATOR SECTION SERIES CONNECTED TO FORM A CLOSED NORMAL COOLINGCIRCUIT, MEANS FOR CIRCULATING A STREAM OF AIR FROM SAID ENCLOSURE INSERIES FLOW OVER SAID SECOND AND FIRST EVAPORATOR SECTIONS, FLOW CONTROLMEANS FOR OPERATING SAID FIRST EVAPORATOR SECTION AS A REHEAT COIL FOROPERATION OF SAID APPARATUS AS A DEHUMIDIFIER, SAID FLOW CONTROL MEANSCOMPRISING A UNITARY VALVE INCLUDING AN INLET CONNECTED IN SAIDREFRIGERANT CIRCUIT BETWEEN SAID COMPRESSOR AND SAID CONDENSER AND ANOUTLET CONNECTED TO SAID CIRCUIT BETWEEN SAID FLOW RESTRICTOR AND SAIDFIRST EVAPORATOR SECTION AND A VALVE PORT BETWEEN SAID INLET AND OUTLETCONNECTIONS AND MEANS OPERABLE UPON OPENING OF SAID VALVE PORT FORRESTRICTING FLOW OF REFRIGERANT FROM SAID FIRST EVAPORATOR SECTION TOSAID SECOND EVAPORATOR SECTION WHEREBY SAID FIRST EVAPORATOR SECTIONFUNCTIONS AS A REHEAT COIL WHEN SAID VALVE PORT IS OPEN.